[Comparative study of two methods for the extraction of yolk IgG]

Extraction of specific IgG antibodies from egg yolks of immunized hens is a convenient and economical approach to the production of diagnostic antibody reagents. In this study, two methods for the extraction of yolk IgG were constructed and compared. That either method could extract at least 15 mg of yolk IgG preparation from 1 ml of egg yolk of hyperimmunized hens clearly indicates that both methods are reliable and efficient. Yolk IgG preparations obtained by method II were purer and possessed higher antibody activity than the yolk IgG preparations produced by method I, so method II is superior to method I. Nevertheless, the yolk IgG preparations produced by method I and method II contained 22% and 16% unrelated proteins respectively. Therefore, these two methods should primarily be used for the rough extraction of hens yolk IgG antibodies. If yolk antibody reagents with higher purity are required, the yolk IgG preparations produced by both methods should be further purified.